<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>

</head>
<body>
    <div class="father">
        <div class="son"></div>
    </div>
    <script>
        var father=document.querySelector('.father');
        var son=document.querySelector('.son');
        father.addEventListener('mouseover',function(){
            
        })
        //mouseover鼠标经过自身盒子会触发,经过子盒子还会触发,mouseenter只会经过自身盒子触发
        //跟mouseenter搭配 鼠标离开mouseleave同样不会冒泡
    </script>
</body>
</html>